1. Field of the Invention
This invention relates to a medical device for the transfer of substances (or device for transfer of medical substance). More particularly, the present invention relates to improvements in and concerning a medical device for the transfer of substances such as in an artificial lung or artificial kidney.
2. Description of the Prior Art
Various medical devices have been made available to date for the transfer of substances. As one version of an artificial lung, there has been known a hollow fiber type artificial lung which comprises a cylindrical housing, a hollow fiber bundle of a plurality of gas-exchange hollow fiber membranes and inserted within the housing, an oxygen chamber defined by the outer surfaces of the hollow fiber membranes and the inner wall surfaces of the housing, an oxygen inlet and an oxygen outlet both communicating with the oxygen chamber, partitions supporting opposite ends of the hollow fiber membranes fixed in position and isolating them from the oxygen chamber, and a blood inlet and a blood outlet communicating with the interior spaces of the hollow fiber membranes (Japanese Utility Model Disclosure (Jikkai) No. 138,947/1980. As one version of the artificial kidney, there has been known a hollow fiber type artificial kidney which comprises a cylindrical housing, a hollow fiber bundle of a plurality of hollow fiber membranes for dialysis and inserted within the housing, a dialytic chamber defined by the outer surfaces of the hollow fiber membranes and the inner wall surfaces of the housing, a dialytic liquid inlet and a dialytic liquid outlet communicating with the dialytic chamber, partitions supporting opposite ends of the hollow fiber membranes and separating them from the dialytic chamber, and a blood inlet and a blood outlet communicating with the interior spaces of the hollow fiber membranes (Compendium of Chemistry, Vol. 21 "Chemistry of Medical Materials," pages 144-146, published on Nov. 25, 1978 by Gakkai Shuppan Center Ltd.).
In any of these conventional medical devices for the transfer of substances, however, the blood inlet and the blood outlet are formed with headers (blood distribution members) fastened to the opposite ends of the cylindrical housing. Generally for the purpose of preventing leakage of blood, these headers are sealed by being attached as tightly pressed to the partitions through the medium of O-rings of soft rubber fitted in grooves formed in the inner surfaces of the headers along the peripheries thereof. In a device of the kind sealed by this method, however, there is a possibility that, after a prolonged service, the partition materials (potting materials) at the opposite end faces of the device will cave in under the pressure of the O-rings and induce the phenomenon of blood leakage. If the O-rings are not neatly fitted in the aforementioned grooves, no blood leakage will occur immediately after the device has been assembled. When the device is heated as during sterilization with ethylene oxide gas, for example, leakage of blood starts to occur through the O-rings. It is, therefore, difficult for the O-rings to be safely checked for blood leakage before the device is sterilized.
Further, Schnell U.S. Pat. No. 4,283,284 discloses a hollow fiber dialyzer end seal system having an inner sleeve and an outer sleeve at both ends formed coaxially each other, holding each end of a bundle of hollow fibers in the inner sleeve by potting agents, contacting a seal ring of an end closure member with each end of the inner sleeve to fix with an enlarged manifold end by screw means and sealing by injecting a sealant partially into a space formed between the inner and outer sleeves and the end closure member through holes. However, in such end seal system, not only a large amount of the sealant is required because of large space, but also it is feared that a dialytic solution may leak through a gap between the enlarged manifold ends and the outer sleeves to invade into the space because the space lacks the sealant. Further, the potting agent contracts after curing, so it is feared that the dialytic solution leaks into a space between the potting agent and the end closure member through the gap between the inner sleeve and the potting agents.
An object of the present invention, therefore, is to provide a medical device for the transfer of substances which is provided with a highly reliable, safe sealing structure.